Air

May 01, 2005

Take a deep breath, and you play your part in the constant recreation of the atmosphere of the earth. The mixture of gases that wraps itself like a gossamer mantle around our planet not only makes life possible; life in turn has its effect on the planetary atmosphere.

It was not ever thus. Primordial earth’s atmosphere contained no oxygen. Then life appeared in the oceans; eventually micro-organisms evolved that used sunlight to produce energy. The byproduct of this photosynthesis was oxygen, which was released into the atmosphere. Carbon was trapped in the fossilized bodies of these micro-organisms and fell to the ocean floors, and over aeons became fossil fuels. Slowly the earth became a planet with a cooler, oxygen-rich atmosphere, and the blossoming of life began in earnest. The earth’s atmosphere, made up of a delicately balanced blanket of gases, traps enough heat to sustain life. These fundamental gases shape the environmental conditions on the planet, such as rainfall and evaporation levels.

But as humans have cleared critical photosynthesizing plants and organisms, and burned more and more fossil fuels, the balance that made most life on earth possible has been upset. Levels of atmospheric carbon dioxide and other polluting gases have been rising steadily since the Industrial Revolution, and with disastrous results.

These gases create a ‘greenhouse effect’, thickening the natural canopy of gases in the atmosphere and causing more heat to become trapped. As a result, the global temperature is increasing, throwing the world’s climate out of its natural balance and into chaos.

The global temperature is set to rise by between 1.5 and 5.8°C and sea level by between 10 and 90 cm, as a result of global warming. The impacts, particularly of changes in rainfall, are likely to be severe, especially in many developing countries. Any action taken now – to reduce carbon emissions, for example – will have a delayed reaction as global temperatures continue to rise. But to take no action at all – effectively the preferred policy worldwide – is simply to invite disaster.

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Approaching storm, Arizona, US Scientists believe that higher global temperatures will result in more 'extreme weather events' such as storms, floods and droughts. The nine hottest years since records began all occurred in the 1990s and 2000s.

Our next breaths, yours and mine, will sample the snorts, sighs, bellows, shrieks, cheers and spoken prayers of the prehistoric and historic past.'Harlow Sharpley, 'Beyond the Observatory'

Tank, Kuwait War's effects on the environment can be catastrophic. An estimated 13,700 tonnes of toxic smoke poured daily into the atmosphere from the hundreds of oil wells set on fire during the first Gulf War. The smoke blew over hundreds of kilometres, inflicting respiratory and carcinogenic damage on those who breathed it in.

Airplane over housing, Hong Kong The Intergovernmental Panel on Climate Change (IPCC) report in 1999 found that aircraft are responsible for 3.5 per cent of greenhouse gas emissions worldwide. Flight is one of the fastest-growing emission sources, and no technological fixes are in sight.

Aurora Borealis (Northern Lights), Norway In Finnish they are called revontulet - 'fox fires' - which comes from an old story of the arctic fox starting fires or spraying up snow with its brush-like tail. The prosaic version is that the sun gives off high-energy charged particles that travel out into space. When this 'solar wind' of particles collides with the gases in the atmosphere at the magnetic poles they start to glow, producing the spectacle that we know as the auroras - like aurora borealis, the Northern Lights.

Windmills at Campo de Criptana, La Mancha, Spain People have used the wind's power as a source of energy for many centuries. The ability to harness the wind to drive grinding stones for wheat probably arose in Persia and the knowledge came to Europe with returning Crusaders. These 16th-century windmills in La Mancha, Spain, were immortalized in Cervantes' novel, Don Quixote.

AIR – THE FACTS

The dominance of coal, oil and natural gas as our sources of energy has released large quantities of carbon previously locked in underground rock layers and has increased the atmospheric concentration of carbon dioxide by a third (34%) since 1750. Some 60% of that increase has happened since 1959.

The global warming caused by this greater concentration of carbon in the air is producing an anticipated speed of climate change greater than anything seen for at least 10,000 years.

Among the anticipated consequences of increased global temperatures are: